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BUG: KASAN: slab-out-of-bounds in should_fault_in_pages fs/gfs2/file.c:785 [inline]
BUG: KASAN: slab-out-of-bounds in gfs2_file_buffered_write+0x576/0x900 fs/gfs2/file.c:1070
Read of size 8 at addr ffff888065c68700 by task syz.3.526/6548

CPU: 1 PID: 6548 Comm: syz.3.526 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 should_fault_in_pages fs/gfs2/file.c:785 [inline]
 gfs2_file_buffered_write+0x576/0x900 fs/gfs2/file.c:1070
 gfs2_file_write_iter+0xfaf/0x1240 fs/gfs2/file.c:1145
 do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 iter_file_splice_write+0x699/0xcc0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe1/0x130 fs/splice.c:956
 splice_direct_to_actor+0x4ea/0xc10 fs/splice.c:902
 do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
 do_sendfile+0x5fc/0xeb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f36d19eb819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f36cfc45028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f36d1c64fa0 RCX: 00007f36d19eb819
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f36d1a81c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f36d1c65038 R14: 00007f36d1c64fa0 R15: 00007fffbc4ced58
 </TASK>

Allocated by task 6548:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc_array include/linux/slab.h:647 [inline]
 kcalloc include/linux/slab.h:676 [inline]
 iter_file_splice_write+0x19f/0xcc0 fs/splice.c:628
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe1/0x130 fs/splice.c:956
 splice_direct_to_actor+0x4ea/0xc10 fs/splice.c:902
 do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
 do_sendfile+0x5fc/0xeb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888065c68600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes to the right of
 256-byte region [ffff888065c68600, ffff888065c68700)
The buggy address belongs to the page:
page:ffffea0001971a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x65c68
head:ffffea0001971a00 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0001db5900 0000000900000009 ffff888016c41b40
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5678, ts 129095324189, free_ts 128333518753
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 __kmalloc+0x1cd/0x330 mm/slub.c:4408
 kmalloc include/linux/slab.h:612 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 new_dir fs/proc/proc_sysctl.c:959 [inline]
 get_subdir fs/proc/proc_sysctl.c:1004 [inline]
 __register_sysctl_table+0xa1f/0x1230 fs/proc/proc_sysctl.c:1353
 neigh_sysctl_register+0x9b0/0xa90 net/core/neighbour.c:3718
 addrconf_sysctl_register+0xac/0x1b0 net/ipv6/addrconf.c:7146
 ipv6_add_dev+0xbf3/0x1190 net/ipv6/addrconf.c:454
 addrconf_notify+0x66f/0xf00 net/ipv6/addrconf.c:3576
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 register_netdevice+0x12a6/0x1710 net/core/dev.c:10454
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:317 [inline]
 nsim_create+0x32d/0x3e0 drivers/net/netdevsim/netdev.c:365
 __nsim_dev_port_add+0x698/0xab0 drivers/net/netdevsim/dev.c:1312
 nsim_dev_port_add_all+0x37/0x100 drivers/net/netdevsim/dev.c:1372
 nsim_dev_probe+0x763/0x9c0 drivers/net/netdevsim/dev.c:1513
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 __free_pages_ok+0x89f/0x940 mm/page_alloc.c:1643
 free_nonslab_page+0xe2/0x150 mm/slub.c:3540
 kvm_free_memslots virt/kvm/kvm_main.c:950 [inline]
 kvm_destroy_vm virt/kvm/kvm_main.c:1254 [inline]
 kvm_put_kvm+0x1251/0x17d0 virt/kvm/kvm_main.c:1283
 kvm_vm_release+0x42/0x50 virt/kvm/kvm_main.c:1306
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff888065c68600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888065c68680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888065c68700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888065c68780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888065c68800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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